化工学报 ›› 2021, Vol. 72 ›› Issue (S1): 146-152.DOI: 10.11949/0438-1157.20201616

• 流体力学与传递现象 • 上一篇    下一篇

一种带引射器和经济器的CO2跨临界制冷系统

李敏霞(),詹浩淼,王派,刘雪涛,李昱翰,马一太   

  1. 天津大学中低温热能高效利用教育部重点实验室,天津 300350
  • 收稿日期:2020-11-10 修回日期:2021-02-05 出版日期:2021-06-20 发布日期:2021-06-20
  • 通讯作者: 李敏霞
  • 作者简介:李敏霞(1971—),女,博士,教授,tjmxli@tju.edu.cn
  • 基金资助:
    国家自然科学基金项目(51876135);空调设备及系统运行节能国家重点实验室开放基金项目(ACSKL2018KT02)

A CO2 transcritical refrigeration system with ejector and economizer

LI Minxia(),ZHAN Haomiao,WANG Pai,LIU Xuetao,LI Yuhan,MA Yitai   

  1. Low and Medium Grade Energy of Ministry of Education, Tianjin University, Tianjin 300350, China
  • Received:2020-11-10 Revised:2021-02-05 Online:2021-06-20 Published:2021-06-20
  • Contact: LI Minxia

摘要:

在蒸发温度较低的工况下,CO2跨临界循环高低压差过大,运行效率下降。针对CO2跨临界循环特性,提出了一种带引射器和经济器的CO2跨临界制冷系统,通过引射器部分回收工质膨胀功减小能量损失,可增加制冷量;合理设计CO2压缩机和中间补气孔,采用经济器进行中间补气可减少系统压缩过程的能量损失。构建了热力学模型,研究表明该系统在较低蒸发温度工况下,相比于基础CO2跨临界制冷系统系统性能可提升40%左右,其中压缩机排气温度可降低40℃左右,有利于系统稳定运行。同时对准二级压缩过程中分段效率计算问题提出近似公式,在一定范围内相比于传统计算方式误差从5%降低至2%。

关键词: 二氧化碳, 跨临界循环, 引射器, 经济器, 中间补气

Abstract:

Under the condition of low evapouration temperature, the difference between the highest and the lowest pressure of CO2 transcritical cycle is excessively large, and the operating efficiency decreases. For CO2 transcritical cycle characteristics, a CO2 transcritical refrigeration system with an ejector and an economiser is proposed. Recycling part of the refrigerant expansion work using the ejector reduces energy loss and increases the refrigerating capacity. Better design of the CO2 compressor and the vapour injection port, and use of economizer for intermediate air supplement can reduce the energy loss of the system compression process. Research shows that the system performance can be increased by about 40% compared with the basic CO2 transcritical refrigeration system under the condition of lower evaporating temperature,the compressor discharge temperature can be reduced by about 40℃, which is conducive to the stable operation of the system. And an approximate formula is proposed for the calculation of the segmentation efficiency in the quasi-two-stage compression process, and the error is reduced from 5% to 2% in a certain range compared with the traditional calculation method.

Key words: carbon dioxide, transcritical cycle, ejector, economiser, vapour injection

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